Portageville Bridge Replacement Visual Impact Analysis

Client:

Service:

Status:

Share This Project

Overview

The Portageville Bridge, also known as the High Bridge, is considered to be the vital link along the Southern Tier Route, crossing the Genesee River in Letchworth State Park in Portageville, NY. Unfortunately, it is the weakest link on the line. Built in 1875, the historic 820-foot steel viaduct can no longer meet the demands of a Class 1 Heavy Freight Railroad. Norfolk Southern needed to find a solution for this tired workhorse. They called upon Modjeski and Masters, a familiar and trusted bridge engineering firm, to guide them through the New York State Environmental Quality Review (SEQR) process, the necessary first step to restore and optimize the Southern Tier Route’s capacity, without impacting the scenic park viewshed.

Modjeski and Masters began by inspecting and rating the existing bridge, which confirmed the near-exhausted useful life and limited load-carrying capacity of the structure. Construction resulting from an intensive rehabilitation would likely interrupt rail operations on the Southern Tier Route. Alternatives to such rehabilitation included a complete replacement of the bridge on an adjacent parallel alignment. Modjeski and Masters engineers developed conceptual bridge replacement designs. Our in-house bridge visualization designer then developed photo-realistic renderings of the concepts from likely vantage points of park visitors. The renderings were used to successfully convey the concepts to the railroad and the general public. Design visualization was also employed for a Visual Impacts Analysis (VIA) to assess potential significant adverse impacts to the scenic viewsheds. The renderings, a key part of the VIA, would help determine the replacement designs that complement, rather than dominate, the scenic viewshed.

Following the VIA, Modjeski and Masters actively worked with Norfolk Southern to determine a safe, economical and aesthetically viable bridge replacement type. Our bridge experts then completed preliminary design, and are now performing services for final design of the 483-ft replacement arch span. It can be said that the Portageville Bridge is symbolic of Modjeski and Masters’ longstanding and continued relationship with Norfolk Southern. As in the past, our knowledgeable experts are entrusted with helping the railroad maintain the Portageville Bridge, and keep operations moving on the Southern Tier Route.

Description

Tasks Performed

Preliminary Inspection

Railroad Services

Technical Access

Alternatives Matrix

Replacement Structure – Design (Conceptual, Preliminary & Final)

Design Visualization

Track Geometry Design

Bridge Geometry

Length of Spans:

Existing Typical Truss Span Length – 100 feet

New Main Arch Span Length – 483 feet

Total Project Length – 819 feet

Tracks on Structure – One railroad track

Testimonial

“We recognized that the bridge was at the end of its life, but look forward to the next generation bridge to be just as iconic.”- Public Involvement Participant